How to create table of content in markdown file

#create_toc.rb
unless ARGV.empty?
  File.open(ARGV.first, 'r') do |f|
    f.each_line do |line|
      forbidden_words = ['Table of contents', 'define', 'pragma']
      next if !line.start_with?("#") || forbidden_words.any? { |w| line =~ /#{w}/ }
      title = line.gsub("#", "").strip
      href = title.downcase.gsub(" ", "-").gsub("--", "-").gsub(/'|\(|\)|\/|,|\./,"").gsub('á','a').gsub('é','e').gsub('í','i').gsub('ó','o').gsub('ú','u').gsub('Í','i')
      puts "  " * (line.count("#")-1) + "* [#{title}](\##{href})"
    end
  end
else
  puts "Usage: ruby create_toc <md file>"
end

ruby create_toc.rb path/to/README.md